code: def exponential_sleep(
      self, previous_attempt_number, delay_since_first_attempt_ms
  ):
      exp = 2**previous_attempt_number
      result = self._wait_exponential_multiplier * exp
      if result > self._wait_exponential_max:
          result = self._wait_exponential_max
      if result < 0:
          result = 0
      return result
  
imports: import random
  import six
  import sys
  import time
  import traceback
label_desc: Use image node_id 8 for calling the Retrying obj's underlying member method code with example usage: obj.exponential_sleep(previous_attempt_number, delay_since_first_attempt_ms) and returns: result